Daniel Radcliffe has revealed he is on blood pressure medication.

The 25-year-old actor admitted he has to take the pills and go for regular check-ups to manage the debilitating cluster headaches he suffers from.

"You have to be on blood pressure medication and have an ECG (electrocardiography heart monitor) every so often... but don't worry, I'm perfectly fine," he told The Guardian.

Dan, who stars in rom-com What If alongside Zoe Kazan and Adam Driver, revealed he suffered from cluster headaches in 2012.

"I was in the middle of these weird things called 'cluster headaches'. It's very rare evidently, but it's exceptionally painful. It makes a migraine look quite tame,'' he told The Independent.

"At the time I thought I was being a wuss. I was taking 12 (strong painkillers) a day and going, 'Why do I still have a headache?'"' the former Harry Potter star added.